(1) Field of the Invention
The present disclosure is related to an air cleaner that takes in air discharged from a fixing device and the like included in an image forming device such as a printer, a copier, or a multifunctional peripheral (MHP), causes the air from the fixing device and the like to pass through a filter, and discharges the filtered air.
(2) Related Art
Conventionally, a fixing device, etc., included in an image forming device such as a printer or a copier may generate undesirable airborne substances such as volatile organic compounds (VOCs) and the like. Such undesirable airborne substances, when discharged to the outside of the image forming device, may negatively affect office environment. Thus, in order to achieve a comfortable office environment, a conventional image forming device is provided with a mechanism that takes in air from the image forming device, which contains the undesirable airborne substances discharged from the fixing device, etc., causes the air from the image forming device to pass through a filter, and discharges the filtered air.
Such a mechanism is commonly referred to as an air cleaner, and typically includes, in addition to a filter, a discharge fan and an air duct.
Recently, more interest is being directed to maintaining a clean office environment. This trend gives rise to the necessity of improving filter performance of air cleaners and thereby reducing the amount of undesirable airborne substances discharged to the outside of image forming devices to as small an amount as possible. Filter performance may be improved, for example, by increasing filter surface area and filter thickness. However, increasing filter thickness unfortunately brings about an increase in depth-direction length of image forming devices, which results in inefficient use of office space. As such, typically, filter surface is increased to improve filter performance.
For example, Japanese Patent Application Publication No. 2002-014583 (referred to in the following as Patent Literature 1) discloses one example of a technology for achieving such an improvement in filter performance without increasing the overall size of an image forming device. In specific, Patent Literature 1 discloses an air cleaner (a dust removing device) that has a pleated filter (i.e., a pleats part 6) that achieves both compact size and increased filter surface area. In addition, Patent Literature 1 discloses a structure where a cross-sectional area of an air flow path in the air cleaner, which guides air from the image forming device containing undesirable airborne substances to the filter, increases considerably upon reaching an inlet of a part where the filter (i.e., the pleats part 6) is accommodated, and where the inlet and the filter are located close to one another.
Accordingly, the air cleaner disclosed in Patent Literature 1 improves filter performance without increasing overall image forming device size.
Meanwhile, as described above, Patent Literature 1 discloses a structure where the air flow path in the air cleaner expands considerably upon reaching the inlet of the part where the filter is accommodated, and where the inlet and the filter are located close to one another. This structure causes air containing undesirable airborne substances, upon being taken in to the part where the filter is accommodated via the inlet, to be mainly guided towards an area of the filter that faces the inlet, before spreading over the entirety of the surface of the filter. This results in the filter capturing the undesirable airborne substances mainly at an area thereof facing the inlet, which then results in a decrease of filter performance (i.e., the ability of capturing undesirable airborne substances) occurring at a faster rate at the area facing the inlet than at other areas of the filter. As a result, filter clogging is accelerated at the area facing the inlet, which shortens filter lifetime.
In view of such technical problems, the present disclosure aims to provide an air cleaner that suppresses a local decrease in filter performance, and an image forming device including such an air cleaner.